Though US Secretary of State John Kerry is eager to gain Beijing's cooperation on issues including Pyongyang's nuclear test and the South China Sea, major achievements are unlikely to come from his upcoming China visit, observers say.

Kerry began his Asian tour in the Laotian capital of Vientiane on Sunday and plans to continue on to Cambodia and China.

Insiders said the stop in China was added to Kerry's itinerary after the Democratic Republic of Korea announced on Jan 6 it had successfully tested a hydrogen bomb.